For which of the following would the lowest ratio of operating expenses to gross income be incurred by the landlord?

The lowest ratio of operating expenses to gross income is typically found in a net-leased retail store due to the specific nature of net leases. In a net lease arrangement, the tenant is responsible for a significant portion of the operating expenses, which can include property taxes, insurance, and maintenance costs, in addition to the base rent. This structure effectively reduces the landlord’s liability for these expenses, leading to a lower overall ratio of operating expenses to gross income.

In contrast, resorts and apartment buildings often incur higher operational costs due to the comprehensive services and amenities they provide. Office buildings have their own maintenance and operational challenges, adding to the overall expense. Therefore, while these property types serve various markets with different needs, the net-leased retail store stands out for its efficiency in minimizing the landlord's direct financial responsibilities, resulting in a more favorable operating expense ratio.